Plasma Amino Acids in Dogs with Osteochondrosis or Hip Dysplasia

Radiography of the hip joints of mature dogs has shown that hip dysplasia is quite common in many middle and large size breeds in Norway. The heritability of hip dysplasia has been estimated in several studies to be between 0.2 and 0.6 (Hedhammar et al 1979). This indicates that environmental factors are important for development and severity of hip dysplasia.     

Thrombin Generation in Zebrafish Blood

To better understand hypercoagulability as an underlying cause for thrombosis, the leading cause of death in the Western world, new assays to study ex vivo coagulation are essential. The zebrafish is generally accepted as a good model for human hemostasis and thrombosis, as the hemostatic system proved to be similar to that in man. Their small size however, has been a hurdle for more widespread use in hemostasis related research. In this study we developed a method that enables the measurement of thrombin generation in a single drop of non-anticoagulated zebrafish blood. Pre-treatment of the fish with inhibitors of FXa and thrombin, resulted in a dose dependent diminishing of thrombin generation, demonstrating the validity of the assay. In order to establish the relationship between whole blood thrombin generation and fibrin formation, we visualized the resulting fibrin network by scanning electron microscopy. Taken together, in this study we developed a fast and reliable method to measure thrombin generation in whole blood collected from a single zebrafish. Given the similarities between coagulation pathways of zebrafish and mammals, zebrafish may be an ideal animal model to determine the effect of novel therapeutics on thrombin generation. Additionally, because of the ease with which gene functions can be silenced, zebrafish may serve as a model organism for mechanistical research in thrombosis and hemostasis.     

DNA fingerprint variation in some blackberry species (Rubus subg.Rubus,Rosaceae)

We have analysed samples from Sweden, Denmark, and Germany of six facultatively apomictic blackberry species to investigate the accordance between a taxonomy based on morphological characters on the one hand, and distribution of genetic variation estimated by DNA fingerprinting on the other hand. DNA fingerprint variation was found to be quite restricted in all species investigated. The first taxonomic group included three species related toRubus nessensis, two being characterized by one very widespread DNA fingerprint in all three countries and a few rare ones, whereas the third species differed between Sweden and Germany. The second taxonomic group included species related toR. gracilis. Two of these species exhibited very similar DNA fingerprints, whereas the third species deviated clearly. The utilization of DNA fingerprinting as a tool in taxonomy is discussed; most likely this method could become a useful complement to morphology, especially in plant groups with reduced levels of genetic recombination.     

Moose selecting for specific nutritional composition of birch places limits on food acceptability

Despite decades of intense research, it remains largely unsolved which nutritional factors underpin food selection by large herbivores in the wild. We measured nutritional composition of birch foliage (Betula pubescens) available to, and used by, moose (Alces alces) in natural settings in two neighboring regions with contrasting animal body mass. This readily available food source is a staple food item in the diet of moose in the high‐fitness region, but apparently underutilized by moose in the low‐fitness region. Available birch foliage in the two regions had similar concentrations of macronutrients (crude protein [CP], fiber fractions, and water‐soluble carbohydrates [WSC]), although a notably lower variation of WSC in the low‐fitness region. For minerals, there were several area differences: available birch foliage in the low‐fitness region had less Mg (depending on year) and P, but more Ca, Zn, Cu, and Mn. It also had higher concentrations of some plant secondary metabolites: chlorogenic acids, quercetins, and especially MeOH‐soluble condensed tannins. Despite the area differences in available foliage, we found the same nutritional composition of birch foliage used in the two regions. Compared to available birch foliage, moose consistently used birch foliage with more CP, more structural fiber (mainly hemicellulose), less WSC, higher concentrations of several minerals (Ca, Zn, K, Mn, Cu), and lower concentrations of some secondary metabolites (most importantly, MeOH‐soluble condensed tannins). Our study conceptually supports the nutrient‐balancing hypothesis for a large herbivore: within a given temporal frame, moose select for plant material that matches a specific nutritional composition. As our data illustrate, different moose populations may select for the same composition even when the nutritional composition available in a given food source varies between their living areas. Such fastidiousness limits the proportion of available food that is acceptable to the animal and has bearings on our understanding and application of the concept of carrying capacity.     

Body fluid homeostasis and cardiovascular adjustments during submaximal exercise: influence of chewing coca leaves

 The present study was undertaken to determine the haematological and cardiovascular status, at rest and during prolonged (1 h) submaximal exercise (approximately 70% of peak oxygen uptake) in a group (n = 12) of chronic coca users after chewing approximately 50 g of coca leaves. The results were compared to those obtained in a group (n = 12) of nonchewers. At rest, coca chewing was accompanied by a significant increase in heart rate [from 60 (SEM 4) TO 76 (SEM 3) beats · min⁻¹], in haematocrit [from 53.2 (SEM 1.2) to 55.6 (SEM 1.1)%] in haemoglobin concentration, and plasma noradrenaline concentration [from 2.8 (SEM 0.4) to 5.0 (SEM 0.5) μmol · l⁻¹]. It was calculated that coca chewing for 1 h resulted in a significant decrease in blood [−4.3 (SEM 2.2)%] and plasma [−8.7 (SEM 1.2)%] volume. During submaximal exercise, coca chewers displayed a significantly higher heart rate and mean arterial blood pressure. The exercise-induced haemoconcentration was blunted in coca chewers compared to nonchewers. It was concluded that the coca-induced fluid shift observed at rest in these coca chewers was not cumulative with that of exercise, and that the hypovolaemia induced by coca chewing at rest compromised circulatory adjustments during exercise. Accepted: 29 October 1996     

Regulatory pathways in photodynamic therapy induced apoptosis.

Photodynamic therapy is an approved treatment for several types of tumors and certain benign diseases, based on the use of a light-absorbing compound (photosensitizer) and light irradiation. In the presence of molecular oxygen, light-activation of the photosensitizer, which accumulates in cancer tissues, leads to the local production of reactive oxygen species that kill the tumor cells. Mitochondria are central coordinators of the mechanisms by which PDT induces apoptosis in the target cells. Recent studies indicate that concomitant to the permeabilization of the outer mitochondrial membrane (which leads to the release of several apoptogenic factors in the cytosol and to the activation of effector caspases), regulatory signaling pathways are activated in a photosensitizer, PDT dose and cell-dependent fashion. Signaling pathways regulated by members of mitogen activated protein kinases and their downstream targets, such as cyclooxygenase-2, appear to critically modulate cancer cell sensitivity to PDT. Understanding the molecular events that contribute to PDT-induced apoptosis, and how cancer cells can evade apoptotic death, should enable a more rationale approach to drug design and therapy.     

Expression of cystatin-related protein and of the C3-component of prostatic-binding protein during postnatal development in the rat ventral prostate and lacrimal gland

The expression of cystatin-related protein (CRP) and of the C3-component of prostatic-binding protein (PBP) during postnatal development of the rat was studied by Northern blotting, dot blot and in situ hybridisation, and by radioimmunoassay or immunoblotting. In intact male rats, very little or no PBP-C3 could be detected in the prostate at 10 days, but at 20 days there was already strong expression. By in situ hybridisation, the first expression of C3 mRNA was observed at 13 days in the prostate and at 22 days in the lacrimal gland. For CRP, this occurred at 16 and 22 days, respectively. Neither CRP nor C3 was expressed in prepubertal male rats castrated at day 1 or day 10 or in female rats. Androgen treatment of intact male animals did not advance the expression of both mRNAs in the prostate, but did so in the lacrimal gland with first expression of C3 at 19 instead of 22 days and of CRP at 13 instead of 22 days. Identical values were obtained in female rats. Androgen treatment of castrated adult male rats resulted in a more rapid and homogeneous secondary induction. Positive immunostaining for the androgen receptor (AR) was observed in the lacrimal gland at 7 days, but its concentration, estimated by immunoblotting, was still low at 10 days. Maximal levels, reached at 30 days, were markedly higher in male than in female rats. In conclusion, CRP and C3 are induced by androgens in prepubertal rats. The time point of induction, however, is probably determined by other tissue and differentiation-dependent factors in addition to androgens and the AR.